import React, { Component } from 'react'
// 引入store，用于获取redux中的状态
import store from '../../redux/store'


export default class Count extends Component {
  // state = {count: 0}

  componentDidMount(){
    // 检测redux中状态的变化,只要变化,就调用render
    store.subscribe(() => {
      this.setState({})
    })
  }
  //加法
  increment = () => {
    const {value} = this.selectNumber
    store.dispatch({type: 'increment', data: Number(value)})
  }
  // 减法
  decrement = () => {
    const {value} = this.selectNumber
    store.dispatch({type: 'decrement', data: Number(value)})
  }
  // 奇数加
  incrementIfOdd = () => {
    const {value} = this.selectNumber
    const count = store.getState()
    if(count % 2 !== 0){
      store.dispatch({type: 'increment', data: Number(value)})
    }
  }
  // 异步加
  incrementAsync = () => {
    const {value} = this.selectNumber
    setTimeout(() => {
      store.dispatch({type: 'increment', data: Number(value)})    }, 1000)
  }
  render() {
    return (
      <div>
        <h1>当前求和为：{store.getState()}</h1>
        <select ref={c => this.selectNumber = c}>
          <option value="1">1</option>
          <option value="2">2</option>
          <option value="3">3</option>
        </select>&nbsp;
        <button onClick={this.increment}>+</button>&nbsp;
        <button onClick={this.decrement}>-</button>&nbsp;
        <button onClick={this.incrementIfOdd}>当前求和为奇数再加</button>&nbsp;
        <button onClick={this.incrementAsync}>异步加</button>
      </div>
    )
  }
}
